Elevation Grade Calculator
Calculate road or terrain grade, angle, and slope distance.
Elevation Grade:
Understanding Elevation Grade
Elevation Grade (or slope) is a way of expressing the steepness of an incline. It is calculated as the ratio of "rise" (vertical change) to "run" (horizontal distance), typically communicated as a percentage.
Grade (%) = (Rise / Run) × 100
Common Grade Examples
- 0%: Perfectly flat surface.
- 2-3%: Typical maximum grade for high-speed railways.
- 4-6%: Common maximum for major highways and interstates (trucks struggle above this).
- 8-10%: Considered steep for cycling; difficult for average riders.
- 15-20%: Very steep residential streets (e.g., San Francisco or specialized mountain roads).
- 100%: A 45-degree angle (Rise equals Run).
Grade vs. Angle
While often confused, percent grade is not the same as degrees.
- A 100% grade is 45 degrees.
- A 50% grade is roughly 26.6 degrees.
- Slope Angle (θ) = arctan(Rise / Run).
Applications
Civil Engineering: Designing roads with proper drainage (min 0.5%) and safety limits.
Cycling: Categorizing climbs (e.g., Tour de France categories are based on length and grade).
Accessibility: ADA guidelines typically limit wheelchair ramps to a maximum of 1:12 (8.33%).